Process of cracking hydrocarbon oils



Sept 11,' 19341 J. c. MORRELI. Er AL PROCESS OF CRACKING HYDROCARBON OILS Filed Feb. 8. 1930 Patented Sept. 11, 1934 UNITED sTATEs 1.973.498 rnocEss or cnAciILngG HYDRocARBoN Jacque C. ll-Iorrell and Gustav 'Eglof Chicago, lll., assignors to Universal Oil Products Company, Chicago, Ill., a. corporation of South Dakota Application February 8, 1930, Serial No. 426,797 1 Claim. (Cl. 196-48) This invention relates to improvements in the art of treating hydrocarbons, and pertains in its specific embodiment to the conversion at elevated temperatures of a multiplicity of hydrocarbon materials to motor fuel of high anti-knock value and accompanying reaction products.

Among the objects of our invention is the utilization as cracking stocks of various hydrocarbon fractions having intermediate boiling point range such as heavy gasoline ends, kerosene or kerosene distillate fractions, pressure distillate bottoms, and various other cuts of products obtained in the renery, and the processing of such materials simultaneously with heavier hydrocarbon cracking stocks on the stocks usually charged to the cracking plant in such a manner as to eiect the best yield and quality of desired products. Frequently the use of such lower boiling hydrocarbon materials in the usual methods of processing is avoided because of vaporization and distillation with no substantial conversion of the intermediate stock' introduced or a portion thereof. In cases of this kind such stocks usually have to be processed in special equipment. In the absence of such equipment these stocks are disposed of at 'small prot.

Frequently the intermediate fractions introduced will contain more or less heavy gasoline ends and whichfwill contaminate the final product from the cracking process `when the usual methods are used, so that the resulting motor fuel will not have a balanced boiling point range. In this l event it becomes necessary, to goto' the expense of adding a low boiling blending stock such as natural or casinghead gasoline to bring the contaminated product to motor fuel specifications. Such contamination usually also results in a lowering of the anti-knock value of the final gasoline. Our invention provides a method where these objectionable features are overcome.

Among other objects of our invention is the processing of hydrocarbons which are within the motor fuel boiling point range and have poor anti-knock properties. Such oils can be introduced into our process in a similar manner as the above mentioned intermediate fractions and treated together with preferably a heavier cracking stock at conditions suitable for procuring a composite anti-knock motor fuel.

The lighter hydrocarbon oil to be processed may not necessarily be a stock obtained outside the process, but may be a product obtained within the process, as for example, the bottoms separated from end point motor fuel obtained in a secondary tower. Such towers are usually operated at lower pressure than the foregoing portion of the cracking process so that the bottoms will require pumping when they are returned to the process.

Our invention comprises in its specific embodiment, the processing of intermediate or light hydrocarbon oil fractions as above described by introducing same preferably directly to the oil owing to or in the heating-zone of a cracking or conversion process and subjecting the mixed oil containing also preferably heavier cracking stock previously introduced, under suitable conditions of treatment at elevated temperature in the production of a maximum of anti-knock motor fuel with a minimum of residual and gaseous products. 'I'he general principle involved is the processing of hydrocarbon oils which are likely to vaporize during pre-treatment and escape subjection to conversion treatment conditions in a direct manner and under suitable conditions soas to obtain the desired yield and products from the plurality of charging stocks.

Mixing of the various oils prior to their introduction to the cracking process as sometimes practiced does not accomplish the purpose or derive the benefits obtained in the practice of our invention, since in such practice one must of necessity depart from the method of simultaneously cracking the plurality of stocks according to our invention. The invention will be more readily understood by referring to the accompanying drawing which illustrates in a somewhat schematic and diagrammatic manner certain preferred embodiments of .the process of our invention and will be described below.

Temperature and pressure conditions used in the process vary, depending upon the character of the various combinations of oil processed and the products desired, for instance, thetemperature of the oil leaving the heating element on its way to the reaction zone may vary from 800 to 1200 F., more or less, and the pressure may vary fiim high superatmospheric pressure to atmosp eric or sub-atmospheric pressure. Differential pressures may be used inthe process.

Referring to the drawing, which is a diagrammatic elevational Iview of one type of apparatus utilized in carrying out our invention, the heavier cracking stock is introduced through line 1 and valve 2 to the suction side of the'pump 3 and is pumped through line 4 and valve 5 to the dephlegmator 6 where it is'preheated by heat interchange with the vapors from the cracking zone. The preheated cracking stock together with condensed vapors flow downward through line 7 and valve 8 to the suction side of the pump 9 from which they are pumped through line 10 and valve 11 to the heating element l2 located in heating zone 13. A portion or all of the oil pumped by pump 3 may ow through line 14 and valve l5 into line 10 leading to the heating element by suitable adjustment and regulation of valve 5 in line 4 and valve 15 in line 14. 'Ihe lighter cracking stock may be introduced through line 16 and valve 17 to the suction side of pump 18 and pumped through line 19 and valve 20 in a manand valve 37 in line 38 closed.

, dephlegmator 6 pass through the line ner and as is illustratedby its passage through in whole, by pump 62 through line 63 into the line 19 with valve 21 open and valve 22 in line lines 23 and 19 by suitable adjustment of valves 23 closed, the oil entering line 10 and mixing 64 and 55,-in line 56, valve 22 inline 23 and valve with the ilow of the heavier cracking stock and 20 in line 19 and the ow directed to the heating reflux condensate from the dephlegmator passelement as previously described for charging the ing tothe heating element; Or a portion, or ithe lighter charging stock. If lighter cracking stock whole flow of the lighter' charging stock may be is not introduced from an outside source when the directed through line 24 and valve 25 to any suitsecondary tower is used, pump 18 can be omitted. able point in the heating element by the obvious It may also be omitted when using a secondary regulation and adjustment of valves 21 and 25. tower except when it is desired to pump reflux The `heated Vmaterials or productsl leave the condensate from the secondary tower to the top heating element through line 26 and valve 27 ofthe dephlegmator. and enter the reaction chamber 28 where the re- As a specic illustration of one embodiment of action continues and vaporization and separation the practice of our invention and the results obof non-vaporized materials occur. Materials tained; i withdrawn from this reaction zone during the A reduced Mid-continent crude oil of 20-22 period when the process is being brought to op- A. P. I. gravity constituting of the total erating conditions or removed during the operacracking stock charged to the process is introtion may be withdrawn through line 29 and valve duced into the dephlegmator of the unit. Kero- 30 which may lead to storage or for subsequent sene distillate of 37438 A. P. I. gravity derived suitable processing by means. not shown. The from the same crude and constituting 20% of vaporous and gaseous products leave the reaction the total cracking stock charged to the process is zone through line 31 and valve 32 and enter near pumped into the mixture of reflux condensate the bottom of the dephlegmating zone 6, where and heavier charging stock being pumped to the the vapors may be subjected to heat interchange heating element. The temperature and pressure and/or cooling. The vapors and gases from the on the processed materials leaving the heating 33 and may elementare approximately 930 F. and 250'pounds. be directed in a manner suchas is. illustrated by Uniform pressure is used on the entire system. the passage of these vapors andegases through The vapors from the reaction chamber are deline 33 with valve 34 open and valve 35 in line 36 phlegrnated and partially converted hydrocarbons The flow is then condensed and returned to the heating zone, the through valve 39 and the condenser and/ or cooler temperature at the top of the dephlegmator being 40 andthe cooled and condensed products flow. maintained at 450 F. by the recirculation of pres-J f through line 41 and valve 42 into thereceiver 43 sure. distillate from the receiver. 'Ifhe pressure where separation of liquid and condensed vapors on the system is regulated by maintaining the and gases is effected. The gases-and uncondensed liquid/level in the receiverand .the releaseof, the vapors leave the system through line 44, regulatuncondensable gases formed during the operation. A ed by valve 45, and the liquid product contain- The yield of lowerpbciling point hydrocarbons, ing motor fuel hydrocarbons is withdrawn pressure distillate so-called, is approximatelylY/tx through line 46, regulated by valve 47. Regulatbased on the total charging stock and contains ed portions of the liquid product in the receiv'er 43 approximately 80% Navy end point gasoline.4 may be discharged through the line 48 and valve The anti-knock value of the gasoline produced 49 tothe suction side of the pump 50 .which pumps from this operation is the equivalent of 41% ben-g this oil through line 51 in a manner such as is zol in Pennsylvania straight run gasoline. v illustrated by the passage through valve 52 to Our invention should not be construed as being m the top of the dephlegmator 6 with valve 53 in limited tov the illustrations which are shown in line 54 and valve 55 in linei56 closed. @the drawing or in the operation cited by way of If a secondary tower is used the vapors passing example, or to the particular plurality of charging from the dephlegmator 6 through the vapor line stocks used, or to the proportions thereof, since 33 to the condenser and/or cooler 40 laredirected within the scope of the operation of the -process 125 as will be illustrated by the flow through line 36 of nur invention many combinations of charging with valve 35 open, valve 34 in line 33 closed and stock and many types of operations may be used. valve 37 inline 38 open. The vapors enter the We claim as our invention; t lower part of the secondary tower 57 and are sub- A process for simultaneously cracking heavy jected to fractionation, the condensate flowing hydrocarbon oil and increasing the anti-knock 1m down through line 58 and valve 59 and the fracvalue of light motor fuel-containing distillate tionated vaporsl and gases leaving through line which comprises passing the motor fuel-contain 38 and valve 37, and flowing to cooling, condensing ing distillate in a restricted stream through a' and collecting means as previously described. heating zone and subjecting the same therein to The distillate from the receiver 43 which is cracking conditions of temperature and pressure, 135 pumped by pump 50 is introduced to the top of discharging the thus heated distillate into a rethe secondary tower through line 54 and valve 53, action zone maintained under cracking conditions valve 52 in the continuation of the line 5l being oftemperatureand pressure, removing the vapors closed. The reflux condensate from the secondand dephlegmating the same in contact with the ary tower 57 flowing downward through line 58 heavsr oil to be cracked, supplying the resultant no and valve 59 may be recirculated, in part, to the mixture of heavy oil and reux condensateto the dephlegmator 6, with or without cooling (cooling heating zone and subjecting the same m the means not shown), by having valve 60 in'y line 61 heating and reaction zones to the cracking condiclosed and pumping the condensate by means 0! tions in admixture with said distillate, and nally pump 62 through lines 63 and" 56 with valves 6,4l condensing the dephlegmated vapors as aproduct 145 and 55 open and valve 22 in line 23 closed. This of the process, condensate which is of an intermediate character l JACQUE C. MORREIL. f may be pumped with or without cooling, in part or GUSTAV EGIDFF. 

